Various medical procedures, particularly cardiology procedures, involve accessing a corporeal vessel or other lumen through a percutaneous sheath. Insertion of the sheath necessarily requires a hole or opening in the vessel wall so that a medical procedure can be performed through the sheath. After the particular medical procedure has been performed, the sheath must eventually be removed from the vessel and the access hole in the vessel wall must be closed.
A number of prior vascular closure devices have been developed to close the hole or puncture in the vessel wall. Closing the hole typically involves packing a resorbable sealing plug at the hole or sandwiching the hole between the sealing plug and an anchor. Examples of prior vascular closure devices are described in U.S. Pat. Nos. 6,179,863; 6,090,130; and 6,045,569 and related patents that are hereby incorporated by reference.
Placing the sealing plug often comprises several steps. First, a puncture site is located. A puncture locator is placed in and through the insertion sheath such that an inlet port in the puncture locator resides outside a distal end of the insertion sheath a predetermined distance. The insertion sheath and puncture locator are inserted through the puncture into a blood vessel. As the distal end of the puncture locator penetrates the blood vessel, blood flows into the inlet port and out of a drip hole via a flow path through the puncture locator.
Blood exiting the drip hole indicates that the puncture locator and insertion sheath have just penetrated the blood vessel. To ensure proper placement of the insertion sheath and subsequently the closure device, the insertion sheath and puncture locator are normally backed out of the vessel until blood stops flowing from the drip hole. Next, the insertion sheath and puncture locator are re-inserted into the blood vessel until blood starts flowing again from the drip hole. Proper depth of penetration and location of the assembly is established by continuing to insert an additional predetermined distance, for example, an operator often inserts the assembly 1 to 2 centimeters further if the blood vessel is a femoral artery. Once the insertion sheath is properly located, the puncture locator is removed and the vascular closure device may be inserted through the sheath and into to the blood vessel.
An anchor at a distal end of the vascular closure device is then deployed within the artery. The anchor is initially aligned with a longitudinal axis of the closure device in a covered nest of the closure device. The anchor is deployed by removing a cover from the anchor and inserting the anchor through the insertion sheath, which allows the anchor to rotate and align itself with an interior wall of the blood vessel. However, sometimes when the anchor is deployed, it tends to remain in or reenter the sheath instead of rotating and aligning with the blood vessel. This phenomenon is termed “shuttling.” Shuttling disables the function, and negates the benefit, of the device. Therefore, it is desirable to have an apparatus that reduces or eliminates anchor shuttle so that the closure device will function as expected.